Crosslinked proteins are being purified from nuclear cataracts. These will be characterized by amino acid analysis, peptide mapping, structural studies and crossreactivities with antibodies to normal lens proteins. Attempts will be made to isolate crosslinks and fluorescent chromophores from cataractous proteins under conditions where modification of these compounds is minimized. The levels of NAD, NADP, NADH2, and NADPH, in the nucleus and cortex of cataractous lenses, will be measured.